This study will evaluate how uncoated asbestos fibers activate normal alveolar macrophages, evaluate mechanisms that might explain the release of cytokines by alveolar macrophages in patients with asbestosis, determine if the p42/p44 kinase and p38 kinase pathways are activated by uncoated or coated asbestos fibers in alveolar macrophages and monocytes, and determine if uncoated or coated asbestos triggers activation of NFkB-alpha transcription factor necessary for cytokine gene expression.